Power transmission clutch and hydraulic control means therefor



Nov. 10, 1936. H. M. ROCKWELL 7 2,060,691

POWER TRANSMISSION CLUTCH AND HYDRAULIC CONTROL MEANS THEREFOR OriginalFiled March 26, 1928 2 Sheets-Sheet l INVENTOR fzay/z M Rae/{well Nov.10, 1936. E L 2,060,691

POWER TRANSMISSION CLUTCH AND HYDRAULIC CONTROL MEANS THEREFOR OriginalFiled March 26, 1928 2 Sheets-Shet 2 VII/[7110114 v/I/IIIIIIIIIIIIIAEIIIII VIII/IA [N VEN TOR A T RNEY Patented Nov. 10, I936POWER TRANSMISSION CLUTCH AND BY- DRAULIC CONTROL MEANS THEREFOR Hugh M.Rockwell, Freeport, N. Y.

Refiled for application Serial No. 264,765, March 26, 1928. Thisapplication May 2, 1932, Serial 19 Claims.

This invention relates generally to improvements in power transmissionclutches, and has particular reference to clutches and actuating meanstherefor especially adapted for use in motor vehicles.

Clutches, for example those usually employed in the automotive art, eachcomprise a clutch member secured to the engine shaft for rotationtherewith in a fixed plane, and a co-operating clutch member. secured toa power transmission shaft and adapted for axial movement whereby to beselectively moved into and out of engagement with the first-mentionedclutch member. Usually, the axially movable clutch member isspring-pressed to its engaging position, and in order to effectdisengagement, said movable clutch member, as used heretofore, has beenprovided with a circumferentially grooved collar or hub which isconstantly .engaged by a rockable 20 yoke. The yoke is rocked bydepression of a foot pedal or lever with which the yoke is connected bysuitable links and the like. Due to their inaccessibility, the clutchcollars and yokes have been difficult to lubricate, often being entirelyneglected, and hence have been subject to rapid wear, necessitatingadjustments and replacement of parts.

In some instances anti-friction bearings have been employed in order toovercome these lubrication difiiculties, but such bearings have beenobjectionable because they are noisy in operation.

The foregoing and other objectionable features of the prior art areovercome by the present invention, which has as one of its important objects, to provide a clutch with fluid pressure actuating means, wherebyto reduce wear to a minimum.

Another object is to provide such a device which will be hydraulicallyactuated, with oil as the pressure fluid, and wherein noise and thenecessity for frequent manual lubrication are eliminated.

Another object of the invention is to provide an improved mastercylinder for hydraulic systems of vehicles, wherein hydraulic pressureis generated by the application of human energy.

Another object of the invention is to provide a clutch and clutchactuating means of extremely simple construction, which will be durablein service, eiiicient in operation and a substantial advance in the art.

More specifically, the invention contemplates the provision of a clutchwherein the relatively movable clutch members are respectively providedwith a cylinder and cooperating piston so disposed thatwhen a suitablefluid, such as oil under pressure, is supplied to the interior of thecylinder, the clutch members will be disengaged. The fluid is suppliedfrom a master cylinder wherein pressure is generated by depression of afoot pedal, but the invention is not necessarily limited to anyparticular form of master cylinder.

The invention will be readily understood from the following descriptionin connection with the accompanying drawings, wherein one embodiment isshown by way of illustration..

Figure l is a vertical, longitudinal, sectional view through one form ofclutch embodying the invention;

Figure 2 is a fragmentary, transverse, sectional view on line II--II ofFigure 1; i

Fig. 3 is a similar transverse sectional view'on line III-III of Fig. 1;20

Fig. 4 is a vertical, longitudinal, sectional view through the improvedmaster cylinder used for manually controlling the clutch;

Fig, 5 is a diagrammatic plan view of a motor vehicle chassis with myimproved hydraulic 25 clutch and braking system;

Fig. 6 is a fragmentary side elevation showing the relationship betweenthe clutch-actuating master cylinder and the steering gear and engine;30

Fig. 7 is a vertical, longitudinal, sectional view through a modifiedform of master cylinder;

Fig. 8 is a fragmentary, sectional view on line 88 of Fig. '7, and

Fig. 9 is a fragmentary, sectional view through anothermodified form ofmaster cylinder.

The invention is applicable to various types of vehicles and has beenshown in Fig. 5 in association with an automobile chassis, whichincludes a chassis frame I resiliently supported by springs 2 and 3 onfront and rear axles 4 and 5, respectively, the front axle 4 having theusual steerable road wheels 6, and the rear axle 5 having the drivingwheels 1. Power is supplied to the rear wheels I from a motor 8, througha friction clutch 9, change-speed transmission l0, and propeller shaftII to the internal mechanism of the rear axle 5. The front wheels 6 arerotatable on steering knuckles of any ordinary or preferred form, saidsteering knuckles being adjustable about the axes of king pins l2 at theend of the front axle 4, and the steering being accomplished by links l3and I4, operable by a steering gear [5. When a foot pedal IS inassociation with a master cylinder I1 is employed for actuating 55a-hydraulic brake system, as disclosed in my application Serial No.195,197, it is desirable similarly to control the clutch 9.

By referring particularly to Figs. 1, 2, and 3, it will be seen that theclutch 9 has been illustrated as a conventional cone clutch, but it isto be understood that it is equally well adapted for use with either asingle or multiple disc clutch, jaw clutch, or other forms as desired.

In the illustrated embodiment, the crankshaft- 20 of the engine 8 isJ'ournaled at 2| in the crankcase 22, and has a rearwardly extendingportion 23 which constitutes a support for an axially movable clutchelement 24. Said clutch element 24 is in the nature of a truncated conehaving its periphery lined with leather 25 or other suitable frictionmaterial, adapted to engage a correspondingly shaped recess 26 in theengine flywheel 21, which is bolted as at 28 to a flange 29 on thecrankshaft 20. The web portion 30 of the clutch element 24 has securedto it, as by bolts 3|, a central sleeve or hub 32 which islongitudinally bored at 33 and fitted with a cylindrical liner 34, theinterior of which is pref erably reamed to receive the accuratelymachined extremity 35 of the crankshaft extension 23. Said sleeve 32,liner 34, and associated parts are movable longitudinally and rotatablyas a unit with reference to the crankshaft, and the cylindrical liner 34has its rear end closed as at 36, whereby to define a fluid chamber 31into which a suitable fluid, such as oil, under pressure, may beintroduced to' effect or control the longitudinal movements of theclutch member 24. From this it will be evident that the reducedextremity 35 of the crankshaft constitutes in effect a piston which isoperable in the cylinder 34, although said piston is held against axialmovement while the cylinder is capable of such movement upon the piston.In actuation of the device, as will presently be described, the thrustload is taken on the body of oil in the fluid chamber 31, causingrelative movement between the clutch elements while obviating frictionand consequent wear and noise.

The rearward extremity of the hub 32 is preferably formed with a splinefitting 40 for connection with the driving shaft of the transmissioncase, in a manner well known to those well skilled in the art. Normally,the clutch element 24 is held in frictional engagement with the flywheelor clutch element 21 by suitable compression springs 4 l there beingthree such springs in the illustrated embodiment, each disposed in arecess 42 inthe web 30; Said springs 4| are compressed between thebottoms of their respective recesses 42 and wing nuts 43 which areadjustable on the ends of studs 44, projecting rearwardly through theweb 30 and carried by a spider 45 or the like. The spider 45- isrotatable on the crankshaft extension 23 and is held against axialmovement by lock nuts 46 and a thrust washer 41.

In order to supply fluid under pressure to the chamber 31, whereby toeffect disengagement of the clutch, the crankshaft extension 23 isprovided with a central longitudinal bore 50 and an intersectingtransverse bore 51 which is in constant communication with an annulargroove 52 in the bearing sleeve 2la. A conduit 53 has one'end anchoredas at 54 in the crankcase bearin: boss, and extends laterally throughthe side of the crankcase (see Fig. 2) to be accessible for connectionto the master cylinder 19, as will hereinafter be described.

While various types of master cylinders may be employed, I may prefer tomake use of one as illustrated in Fig. 4. Such a master cylinder 19comprises a tubular body 55, preferably made as a casting, having asmooth, cylindrical bore 56, within which is fitted a plunger or piston51, capable of reciprocation. The outer or upper end of the plunger isof a reduced diameter to provide a piston rod 58 which slides through apacking gland 59 and a stop ring 59a, a tight joint being maintained bymeans of packing 60, and said rod 58 carries .at its outer extremity apedal member 61 covered by a rubber pad 62. The pedal member 6| may beconnected in any suitable manner to the rod 58, such as by ascrew-threaded shank 63 engaging in a tapped hole in the end of pistonrod 58. The cylinder 19 is preferably disposed at an inclination in thevertical plane as shown in Figs. 4 and 6, the degree of inclinationbeing dependent upon the particular installation, and in order to adjustthe same longitudinally, the outer surface of the body portion 55 isscrew-threaded as at 64 for cooperative engagement with the threadedinterior of a supporting bracket 65. Said supporting bracket 65 mayconveniently be formed as a part of the steering gear housing, ifdesired, or it may be entirely separate and secured to the side rail orother fixed part of the chassis frame I.

The lower end of the cylinder body 55 has a slightly smaller internaldiameter, and this operative portion of the cylinder is filled with oilor other fluid capable of transmitting pressure.

The oil may be fed by gravity from a suitable reservoir mounted abovethe cylinder, or it may be supplied through a tube 61 from the pressurelubricating system of the motor 8, as illustrated. The tube 61communicates with the cylinder bore 56 adjacent the lower end of theplunger 51, when the latter is in its normal position of rest at theupper end of the cylinder, and is fitted with a coupling 68 forconnection to a nipple 69 in the body 55. The nipple 69 has a restrictedcentral longitudinal oriflce 10 through which oil may flow inwardly to aport 11, which intersects an annular groove 12 in the wall of thecylinder bore 56. The arrangement of the parts is such that when theplunger 51 is in its normal position, as shown in Fig. 4, its lower enduncovers the port 1| and groove 12, permitting free circulation of oilfrom the conduit 61 to the cylinder bore 56, but when the plunger ismoved downwardly by depression of the pedal 6|, communlcation betweenthe port 11 and the cylinder bore 56 is cut off. By virtue of the factthat the orifice 10 is restricted, only a small quantity of oil willpass through it without building up any substantial pressure in thecylinder, and without interfering with the venting of air from thesystem. The port 11 is in*a boss which extends radially from thecylinder body 55 and which is fitted with another nipple 13 to which atube 14 is connected, said tube 14 constituting a return line to theengine crankcase. From this it will be clear that the plunger 51 acts asa cut-off valve for the port 11, obviating the necessity of a checkvalve in the oil supply line 61, and when the port is so cut off, theoil is free to circulate from the conduit 61 to the conduit 14, whenceit is returned to the pressure lubricating system. The lower end of thecylinder I9 is provided with a closure cap 15 in which the other end ofthe conduit 53 is secured by means of a suitable coupling nut 16.

virtue of the fact that the port H is at the uppermost part of the fluidchamber, it is clear that any air in the system will work its way upwardand pass into the crankcase. In order to disengage the clutch, it isonly necessary to step upon the pedal members GI and 62, moving theplunger 51 downwardly in the cylinder bore 56 against the fluid trappedtherein, whereby pressure will be imposed on the fluid and trans mittedthrough the conduit 53, annular groove 52 and bores and 60 to the fluidchamber 31. Such pressure within the chamber 3! acts against thecylinder end wall 36, causing the same to move longitudinally rearward.sleeve 32 and clutch member 24 move with the cylinder 34 against theaction of the springs 4|, causing the leather lined periphery of themember 24 to become disengaged from the recess 26 in the flywheel. Whenthe foot pressure is released from the pedal, the springs 4i restore theclutch member 24 to its normal position, accompanied by return of thedisplaced oil to the cylinder bore 56 and consequent restoration of theplunger 51 to its normal position.

In Figs. 7 and 8, another form of master cylinder is shown, wherein theoil supply pipe 61 and oil return pipe 14 are connected at differentpoints longitudinally in the cylinder. An annular groove 12a and port'H--a are located adjacent the position of rest of the lower end of theplunger 51, as previously described, and another annular groove 16 andport 11 are spaced therefrom substantially at the lower end of theworking portion 56a. of the cylinder. A nipple 69a is threaded into thecylinder to communicate with the port 11, providing a connection for theoil supply pipe 61, and said nipple is provided at its outer end with arestricted orifice 18 through which the oil may flow inwardly. Aspring-pressed check valve 19 is seated within the nipple 69-0. andagainst the end of the orifice 18, and by this arrangement, the oil isfree to flow inwardly when the plunger is at rest at the upper end ofthe cylinder, but will be cut off by oil pressure as the plunger ismoved downwardly. Otherwise, the operation of the device is the same asin the first disclosed form. In each of these cylinders it is preferableto have the parts so proportioned that the packing gland 59 will behigher than the normal oil level indicated in Fig. 7.

It is not necessary to have both the pipes 61 and 14 communicating withthe cylinder 56 at the same point as in Fig. 4, and in this respectanother modification is shown in Fig. 9. Here the oil supply pipe 61 isconnected by a coupling nut 68 and nipple 69 to the lower side of thecylinder body 55 in diametrical opposition to the outlet port ll. Thisarrangement permits freer venting of the system through the port Hwithout possibility of hindrance from the oil coming in through the pipe61. Under normal conditions of operation the plunger in Figs. 4 and 9will not return to their extreme upper positions to uncover the annulargroove 12, and there fore, it will be necessary to occasionally draw thepedal outwardly to such extreme position in order to replenish the oilin the system. If desired, a spring can be employed to positively returnthe The plunger the full distance after each operation, but such springis not really necessary. In that form of the invention shown in Figs. 7and 8, of course, the circulating oil from the pipe 61 maintainssufllcient pressure to uncover the outlet port 1 l-a.

From the foregoing it will be evident that an improved clutch andactuating means therefor have been provided, wherein the clutch iscontrolled hydraulically and free from wearing parts. The constructionisextremely simple, capable of economical manufacture, and constitutes asubstantial advance in the art. The

improved master cylinders are not restricted to use with hydraulicclutches, but may also be employed with equal advantage in fluidpressure braking systems for vehicles. Obviously, the invention issusceptible of numerous further modifications in the details ofconstruction and arrangement of parts, and the right is herein reservedto make such changes as fall within the scope of the appended claimswithout departing from the spirit of the invention.

This application is a re-filing of my application Serial No. 264,765,filed March 26, 1928, in which application the-invention was firstdisclosed to the Patent Oflice.

Having thus described my invention, what I claim is: I

1. In a clutch for automotive vehicles, a rotatable driving element, adriven element coaxial therewith adapted for frictional engagement withsaid driving element and adapted to be moved longitudinallywithreference to the driving element, means for normally maintaining saiddriving and driven members in engagement with each other, substantiallycentral fluid pressure means for moving said driven member out ofengagement with the driving member by direct application of fluidpressure, and manumotive means for controlling the pressure in saidfluid pressure means.

2. In a clutch for automotive vehicles, a rotatable driving element, adriven element coaxial therewith and movable into and out of frictionalengagement with the driving element, said driving and driven elementsbeing respectively connected to axially alined telescoped shafts, springmeans for normally maintaining said frictional engagement between theparts, the opposing ends of the telescoped shafts providing fluidpressure means for moving the driven member out of such frictionalengagement.

3. In a clutch, a rotatable driving element, a driven element coaxialtherewith and movable into and out of frictional engagement with thedriving element, said driving and driven elements being respectivelyconnected to axially alined shafts, spring means for normallymaintaining said frictional engagement between the parts, and actuatingmeans including a fluid pressure cylinder of relatively small diameterrotatable with one of said clutch elements and having a snug sliding fitover the shaft of the other clutch element, the end of thelast-mentioned shaft functioning as a piston within said cylinder.

4. In a clutch, a rotatable driving element, a driven element coaxialtherewith and movable into and out of frictional engagement with thedriving element, spring means for normally maintaining said frictionalengagement between the parts, actuating means including a substantiallycentral fluid pressure cylinder rotatable with one of said clutchelements, and a cooperating piston carried by the other. clutch element.

5. In a clutch, a rotatable driving element, a driven element coaxialtherewith and movable into and out of frictional engagement with thedriving element, spring means for normally maintaining said frictionalengagement between the parts, actuating means including a substantiallycentral fluid pressure cylinder rotatable with one of said clutchelements, a cooperating piston carried by the other clutch element, andmeans for supplying fluid under pressure to said cylinder duringrotation of the parts, whereby to control said actuating means.

6. In combination, clutch elements normally held resiliently inoperative surface engagement with each other, a fluid pressure cylinderfixed with reference to one of the clutch elements and free fromcommunication with the operative engaging surface, a piston operable insaid cylinder and fixed with reference to the other clutch element, andmeans for supplying fluid under pressure to said cylinder whereby todisengage the clutch elements.

7. In combination, clutch elements normally held resiliently infrictional surface engagement witheach other, a fluid pressure cylinderfixed with reference to one of the clutch elements and free fromcommunication with the operative engaging surface, a piston operable insaid cylinder and fixed with reference to the other clutch element, andmeans for supplying fluid under pressure through said piston to theinterior of said cylinder, whereby to disengage the clutch elements.

8. In combination, with a driving shaft and a driven shaft in axialalinement, a clutch member secured to the driving shaft for rotationtherewith in a fixed plane, a cooperating clutch member rotatable withthe driven shaft and movable axially thereon whereby to be capable ofselective engagement with and disengagement from the first clutchmember, a pressure cylinder carried by the axially movable clutch memberand snugly fitting over the adjacent end of the driving shaft, and meansfor supplying fluid under pressure through the driving shaft to theinterior of the cylinder, whereby to effect the relative axial movement.

9. In combination, a driving shaft, a driven shaft, clutch elementssecured to driving and driven shafts respectively and normally inoperative engagement with each other, and hydraulic means fordisengaging said clutch elements, the thrust load being taken on a bodyof oil which causes relative movement between the clutch elements, saidbody of oil being centrally located within one of the shafts.

10. In combination a driving shaft, a driven shaft, clutch elementssecured to driving and driven shafts respectively and normally inoperative engagement with each other, and hydraulic means fordisengaging said clutch elements, the thrust load being taken on a bodyof oil which causes relative movement between the clutch elements, saidbody of oil being centrally located in relation to the axis of thedriving shaft and confined within the driven shaft.

11. Power transmissionmeans comprising, in combination, an engine crankshaft journalled in a plurality of bearings and constituting a drivingshaft, a driven shaft independently journalled but having one endpiloted with reference to one end of the crank shaft, friction clutchelements respectively secured to the crank shaft and the driven shaft,said clutch elements being adapted to be selectively engaged anddisengaged with reference to each other, and manually operatedfluid-pressure means effective between the piloted ends of said shaftsto control engagement and disengagement of the clutch elements.

12. Power transmission means comprising, in combination, an engine crankshaft journalled in a plurality of bearings and constituting a drivingshaft, a driven shaft independently journalled but having one endpiloted with reference to one end of the crank shaft, friction clutchelements respectively secured to the crank shaft and the driven shaft,said clutch elements being adapted to be selectively engaged anddisengaged with reference to each other, and manually operatedfluid-pressure means effective between the piloted ends of said shaftsto control engagement and disengagement of the clutch elements, andmeans for supplying pressure fluid to said control means through one ofthe crank shaft bearings and the adjacent portion of the shaft.

13. Power transmission means comprising in combination, an engine crankshaft journalled in a plurality of bearings, a co-axial driven shaftindependently journalled for rotation and axial movement with referenceto the crank shaft, the end of one of said shafts being piloted withinthe other and leaving therein a pressure chamber, a fly-wheel secured tothe crank shaft, a friction clutch element cooperatively disposed withinthe fly-wheel and secured to the driven shaft, and means for supplyingpressure fiuid to said pressure chamber through the end bearing andadjacent part of the crank shaft whereby to control engagement anddisengagement of said clutch element.

14. In a motor vehicle or the like, in combination'with the motor unithaving an end bearing, a power shaft journalled therein and a variablespeed transmission unit having a transmission shaft in axial alinementwith said power shaft, a clutch providing a disengageable drivingconnection between said power shaft and transmission shaft, and meansfor conducting the actuating pressure fluid to and from said clutchthrough the end bearing of the motorand the center of the adjacentportion of the power shaft.

15. In a motor vehicle or the like, in combination with the motor unithaving an end bearing, a power shaft journalled therein and a variablespeed transmission unit having a transmission shaft in axial alinementwith said power shaft, a clutch providing a disengageable drivingconnection between said power shaft and transmission shaft, said clutchhaving relative movable clutch elements and a central body of oil fortaking the thrust load and causing the relative movement of said clutchelements, oi1-conduct ing means through the end bearing of the motor andin the power shaft to said central body of oil, and means adjacent adriver's seat for controlling pressure of oil in said oil-conductingmeans whereby to control the engagement and disengagement of the clutch.

16. In combination, clutch elements normally in operative engagementwith each other, a driving shaft to which one of the clutch elements issecured, a driven shaft to which the other clutch element is secured,the said shafts having telescoping engagement with each other and beingrelatively movable axially, an oil chamber between the telescoped endsof the shafts, said oil chamber communicating with a bore in the drivingshaft, a bearing for the driving shaft having a chamber thereincommunicating with the bore in the driving shaft, the chambers and thebore being normally filled with oil, and means for creating pressure onthe oil to move said shafts relatively for disengagement of the clutchelements.

17. In combination, an engine having a crank shaft, a driven shaft,clutch elements connected respectively with the crank and driven shafts,said clutch elements normally held resiliently in operative surfaceengagement with each other, a fluid pressure cylinder fixed withreference to one of the clutch elements and free from communication withthe operative engaging surface, a piston operable in said cylinder andfixed relative to the other clutch element and means for supplying fluidunder pressure to said cylinder through the crank shaft to disengage theclutch elements.

1 8. In combination an engine having a crank shaft, a bearing for thecrank shaft, a driven shaft, clutch elements connected respectively withthe crank and driven shafts, said clutch elements normally heldresiliently inoperative surface engagement with each other, a fluidpressure cylinder fixed with reference to one of the clutch elements andfree from communication with the operative engaging surface, a pistonoperable in said cylinder and fixed relative to the other clutch elementand means for supplying fluid under pressure to said cylinder throughthe crank shaft bearing to disengage the clutch elements.

19. 'In combination an engine having a crank shaft, a rear bearing forthe crank shaft, a driven shaft, clutch elements connected respectivelywith the crank and driven shafts, said clutch elements normally heldresiliently in operative surface engagement with each other, a fluidpressure cylinments and free from communication with the operativeengaging surface, a piston operable in said cylinder and fixed relativeto the other clutch element and means for supplying fluid under derfixed with reference to one of the clutch e'le l5 pressure to saidcylinder through the rear crank 20 shaft bearing to disengage the clutchelements.

HUGH M. ROCKWELL.

